Resilient device

ABSTRACT

An intravaginal device has a working portion (e.g., intravaginal urinary incontinence device suppository, tampon) and an anchoring portion comprising at least one member extending beyond at least one end of the working portion to maintain the working portion in place during use.

This application is a divisional of U.S. Ser. No. 11/456,376 filed Jul.10, 2006, the complete disclosure of which is hereby incorporated hereinby reference for all purposes.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a resilient device. More specifically,this invention relates to a device that has a working portion having avariable equivalent diameter, and an anchoring mechanism. The device isuseful, e.g., for reducing or preventing urinary incontinence.

2. Description of the Prior Art

Stress urinary incontinence is a problem for many women. It ischaracterized by leakage of urine during a stressing event, such as acough or a sneeze. Many devices have been designed to reduce or preventstress urinary incontinence. U.S. Pat. No. 5,603,685 teaches inflatabledevices and a means to provide a device that is small for insertion intothe vagina and enlarges to a required shape and pressure to reduce orprevent urinary incontinence. U.S. Pat. No. 6,090,098 teachestampon-like devices, each made with a combination of absorbing and/ornon-absorbing fibrous materials. U.S. Pat. No. 6,645,137 teaches a coilthat expands in the vagina. U.S. Pat. No. 5,036,867 teaches acompressible resilient pessary. U.S. Pat. No. 6,460,542 teaches a highlyshaped rigid pessary. Many patents are drawn to stents that are sizedand designed to keep arteries open.

Despite the teaching of the prior art, there is a continuing need for adevice suitable for insertion into a vagina and useful for reducing orpreventing urinary incontinence. In addition, a need exists to providefor safe and secure anchoring of disposable intravaginal devices.

SUMMARY OF THE INVENTION

These needs have been addressed by present invention. In one embodiment,an intravaginal device includes a working portion and an anchoringportion. The anchoring portion has at least one member extending beyondat least one end of the working portion to maintain the working portionin place during use.

In another embodiment, an intravaginal urinary incontinence deviceincludes a stent having a working portion having opposed faces toprovide support to an associated urinary system; and an anchoringportion to maintain the stent in place during use. The anchoring portionhas at least one member extending beyond at least one end of the workingportion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a device according to the presentinvention;

FIG. 2 is a perspective view of the device of FIG. 1 in the insertionstate.

FIG. 3 is a perspective view of the device of FIG. 1 in the use state.

FIG. 4 is a perspective view of a second device according to the presentinvention;

FIG. 5 is a front plan view of three anchoring portion shapes useful inthe present invention;

FIG. 6 is a perspective view of another device according to the presentinvention;

FIG. 7 is a side view of the device of FIG. 1;

FIG. 8 is a device in a bag that is useful for the present invention;

FIG. 9 is a tool utilized to form the devices utilized in the presentinvention;

FIG. 10 is a tool utilized to heat treat the devices utilized in thepresent invention;

FIG. 11 is a force vs extension curve;

FIG. 12 is a diameter vs pressure curve; and

FIG. 13 is a graph of the diameter versus pressure of the device usingthe linear scale method.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to FIGS. 1-7, there is shown a device 10 according to thepresent invention. The device 10 has a working portion 1 which isgenerally cylindrical in shape and contains faces 9 a and 9 b. Workingportion 1 has an initial equivalent diameter d ranging from about 20 mmto about 170 mm and a length L1 ranging from about 15 mm to about 60 mm.Where the working portion is non-cylindrical, the equivalent diameter isthe maximum distance in millimeters between the faces. As seen in FIG.2, working portion 1 has an insertion (in an applicator or other devicefor insertion) equivalent diameter d2 ranging from about 5 mm to about20 mm. As seen in FIG. 3, working portion 1 has a use equivalentdiameter (in the vagina) d3 ranging from about 5 mm to about 40 mm.Working portion 1 may be made of any elastic material that compressesand recovers with sufficient force to provide the desired effect. In oneembodiment, the working portion 1 is made of Nitinol wire and comprisesalternating sinusoidal struts 2, 3 which intersect and form a strutangle θ. Alternating struts 2, 3 have a length L2 and L3 equal to theworking portion length. The working pressure exerted by working portion1 is determined by the thickness of the wire, the number of wires, thelength of the struts and the strut angle, and the number of times theworking portion is heat treated. The number of wires may range fromabout 1 to about 20. The wires may be separate, twisted, or braided. Forsome applications, the working portion exerts a pressure of from about 5to about 250 cm H₂O in the working state. Device 10 may also have ananchoring portion 4. Anchoring portion 4 is designed to keep the devicein place when in use. Anchoring portion 4 is shaped suitable to keep thedevice in place while in use. Suitable shapes include, but are notlimited to, a basket handle 5, a dog bone 6, and rabbit ears 7, as shownin FIG. 5. The anchoring portion may be made of the same material as theworking portion or they may be made of different materials. The workingportion and anchoring portion may be made as a uni-body construction, ormay be made separately and joined by attachment means, such as siliconetubing. The devices may be treated to provide improved biocompatibility.The device may be placed inside tubing, for example silicone tubing, ormay be dip coated in suitable polymeric materials to improvebiocompatibility.

As used herein the specification and the claims, the term “wire form”and variants thereof relate to a structure formed of at least one wireor wire-like material that is manipulated and optionally secured (e.g.,by welding) in a desired three-dimensional structure.

As used herein the specification and the claims, the term “shape memorymaterial” and variants thereof relate to materials that can be shapedinto an initial shape, which initial shape can be subsequently formedinto a stable second shape. The material is capable of substantiallyreverting to its initial shape upon exposure to an appropriate event,including without limitation mechanical deformation and a change intemperature.

As used herein the specification and the claims, the term “stent” andvariants thereof relate to a device used to support a bodily orifice,cavity, vessel, and the like. The stent is resilient, flexible, andcollapsible with memory. The stent may be any suitable form, including,but not limited to, scaffolding, a slotted tube or a wire form.

Devices according to the present invention may be useful for treating orpreventing urinary incontinence. For this application, the device issized to fit comfortably in the vagina. All of the devices describedbelow may have working portions with initial equivalent diameters offrom about 20 to about 170 mm. Preferably, the working portion has agenerally cylindrical working portion that may have an initialequivalent diameter ranging from about 20 to about 170 mm, preferablyabout 20 to about 45 mm, or more preferably about 30 mm; an insertionequivalent diameter ranging from about 5 to about 25 mm, preferablyabout 10 to about 20 mm, or more preferably about 18 mm; a useequivalent diameter ranging from about 20 to about 40 mm, preferablyabout 25 to about 30 mm, or more preferably about 25 mm; and a lengthranging from about 20 to about 60 mm, preferably about 20 to about 30mm, or more preferably about 25 mm. The anchoring portion extends beyondthe working portion and may have an initial equivalent diameter rangingfrom about 20 to about 60 mm, preferably about 40 to about 60 mm, ormore preferably about 50 mm; an insertion equivalent diameter rangingfrom about 10 to about 25 mm, preferably about 10 to about 20 mm, ormore preferably about 18 mm; a use equivalent diameter ranging fromabout 20 to about 60 mm, preferably about 40 to about 60 mm, or morepreferably about 50 mm; and a length ranging from about 10 to about 50mm, preferably about 20 to about 40 mm, or more preferably about 30 mm.

For a basket stent (having a basket handle-shaped anchoring portion asshown in FIG. 6), the working portion of the device has a length andequivalent diameter in the insertion state, the working state, and theremoval state. The insertion state length may range from about 20 toabout 30 mm, for example about 25 mm. The insertion state equivalentdiameter may range from about 5 to about 20 mm, for example about 18 mm.The working state length at rest and during a cough may range from about20 to about 30 mm, for example about 25 mm. The working state equivalentdiameter at rest may range from about 20 to about 30 mm, for exampleabout 25 mm. The working state equivalent diameter during a cough mayrange from about 15 to about 25 mm, for example about 20 mm. The removalstate length may range from about 20 to about 30 mm, for example about25 mm. The removal state equivalent diameter may range from about 15 toabout 20 mm, for example about 18 mm.

The anchoring portion of the device has a length and width in theinsertion state, the working state, and the removal state. The insertionstate length may range from about 25 to about 40 mm, for example about30 mm. The insertion state width may range from about 15 to about 20 mm,for example about 18 mm. The working state length at rest and during acough may range from about 25 to about 40 mm, for example about 30 mm.The working state width at rest and during a cough may range from about25 to about 35 mm, for example about 30 mm. The removal state length mayrange from about 30 to about 50 mm, for example about 40 mm. The removalstate width may range from about 15 to about 20 mm, for example about 18mm.

For a straight stent, the working portion of the device has a length andequivalent diameter in the insertion state, the working state, and theremoval state. The insertion state length may range from about 25 toabout 60 mm, for example about 45 mm. The insertion state equivalentdiameter may range from about 5 to about 20 mm, for example about 18 mm.The working state length at rest and during a cough may range from about25 to about 60 mm, for example about 45 mm. The working state equivalentdiameter at rest may range from about 20 to about 30 mm, for exampleabout 25 mm. The working state equivalent diameter during a cough mayrange from about 15 to about 25 mm, for example about 20 mm. The removalstate length may range from about 25 to about 60 mm, for example about45 mm. The removal state equivalent diameter may range from about 15 toabout 20 mm, for example about 18 mm.

For a rabbit stent (having “rabbit ear”-shaped anchoring portion, asshown in FIGS. 1, 3 and 7), the working portion of the device has alength and equivalent diameter in the insertion state, the workingstate, and the removal state. The insertion state length may range fromabout 20 to about 30 mm, for example about 25 mm. The insertion stateequivalent diameter may range from about 10 to about 20 mm, for exampleabout 15 mm. The working state length at rest and during a cough mayrange from about 20 to about 30 mm, for example about 25 mm. The workingstate equivalent diameter at rest and during a cough may range fromabout 10 to about 30 mm, for example about 18 mm. The removal statelength may range from about 20 to about 30 mm, for example about 25 mm.The removal state equivalent diameter may range from about 10 to about20 mm, for example about 15 mm. The height of the working portion in allstates may range from about 20 to about 30 mm, for example about 25 mm.

The anchoring portion of the device has a length and width in theinsertion state, the working state, and the removal state. The insertionstate length may range from about 20 to about 50 mm, for example about30 mm. The insertion width may range from about 10 to about 20 mm, forexample about 18 mm. The working state length at rest and during a coughmay range from about 20 to about 50 mm, for example about 30 mm. Theworking state width at rest and during a cough may range from about 20to about 60 mm, for example about 50 mm at the top and from about 10 toabout 50 mm, for example about 25 mm at the bottom. The removal statelength may range from about 20 to about 50 mm, for example about 30 mm.The removal state width may range from about 10 to about 20 mm, forexample about 18 mm.

For a flower stent, the working portion of the device has a length andequivalent diameter in the insertion state, the working state, and theremoval state. The insertion state length may range from about 20 toabout 30 mm, for example about 25 mm. The insertion state equivalentdiameter may range from about 10 to about 20 mm, for example about 15mm. The working state length at rest and during a cough may range fromabout 20 to about 30 mm, for example about 25 mm. The working stateequivalent diameter at rest may range from about 20 to about 35 mm, forexample about 25 mm. The working state equivalent diameter during acough may range from about 15 to about 30 mm, for example about 20 mm.The removal state length may range from about 20 to about 30 mm, forexample about 25 mm. The removal state equivalent diameter may rangefrom about 10 to about 20 mm, for example about 15 mm.

The anchoring portion of the device has a length and width in theinsertion state, the working state, and the removal state. The insertionstate length may range from about 20 to about 50 mm, for example about30 mm. The insertion width may range from about 10 to about 20 mm, forexample about 18 mm. The working state length at rest and during a coughmay range from about 20 to about 60 mm, for example about 30 mm. Theworking state width at rest and during a cough may range from about 20to about 60 mm, for example about 30 mm at the top and from about 10 toabout 50 mm, for example about 20 mm at the bottom. The removal statelength may range from about 20 to about 60 mm, for example about 30 mm.The removal state width may range from about 10 to about 20 mm, forexample about 18 mm.

Devices according to the present invention are stents. As used herein, a“stent” is a device used to support a bodily orifice, cavity, vessel,and the like. The stent is resilient, flexible, and collapsible withmemory. The stent may be any suitable form, including, but not limitedto, scaffolding, a slotted tube or a wire form.

Elements of the devices of the present invention may be made from anyelastic or supereleastic material. Suitable materials include, but arenot limited to metal alloys, for example a nickel-titanium (“NiTi”)alloy known in the art as Nitinol. As is known in the art, there are avariety of ways to process NiTi, including resistance heating andpermanent deformation to create a shape set. Other materials (otheralloys, superelastic alloys or other NiTi compositions) may be utilizedto make devices according to the present invention.

Shape memory is the ability of a material to remember its originalshape, either after mechanical deformation, which is a one-way effect,or by cooling and heating which is a two-way effect. This phenomenon isbased on a structural phase transformation. The first materials to havethese properties were shape memory metal alloys including NiTi(Nitinol), CuZnAl, and FeNiAl alloys. Examples of suitable alloysfurther include Algiloy, Stainless Steel, for example 304 stainlesssteel, and carbon spring steels. The structure phase transformation ofthese materials is known as martensitic transformation.

Shape memory polymers (SMPs) are light, high in shape memory recoveryability, easy to manipulate and process, and economical compared toshape memory alloys. These materials are also useful for devicesaccording to the present invention. There are few ways to achieve theshape memory properties. SMPs are characterized as phase segregatedlinear block co-polymers (e.g., thermoplastic elastomers) having a hardsegment and soft segment that form physical cross-links. The hardsegment is typically crystalline with a defined melting point, and thesoft segment is typically amorphous with a defined glass transitiontemperature. The transition temperature of the soft segment issubstantially less than the transition temperature of the hard segment.Examples of these materials include polyurethanes; polyether amides;polyether ester; polyester urethanes; polyether urethanes; andpolyurethane/urea. SMPs are also formed by covalently cross-linkedirreversible formation of the permanent shape. Different parameters thatcan be tailored for these materials are mechanical properties ofpermanent and temporary shape, customized thermal transitions, andkinetics of shape memory effect. SMPs can be biostable andbioabsorbable. Biostable SMPs are generally polyurethanes, polyethers,polyacrylates, polyamides, polysiloxanes, and their copolymers.Bioabsorbable SMPs are relatively new and include thermoplastic andthermoset materials. Shape memory thermosets may include poly(caprolactone) dimethyacrylates; and shape memory thermoplastics mayinclude combinations of different monomers to prepare polyester basedcopolymers.

When the SMP is heated above the melting point of the hard segment, thematerial can be shaped. This “original” shape can be memorized bycooling the SMP below the melting point of the hard segment. When theshaped SMP is cooled below the glass transition temperature of the softsegment while the shape is deformed, a new “temporary” shape is fixed.The original shape is recovered by heating the material above the glasstransition temperature of the soft segment but below the melting pointof the hard segment. The recovery of the original shape induced by anincrease of temperature is called the thermal shape memory effect.Several physical properties of SMPs other than ability to memorize shapeare significantly altered in response to external changes in temperatureand stress, particularly at the glass transition of the soft segment.These properties include elastic modulus, hardness, and flexibility. Themodulus of SMP can change by a factor of up to 200 when heated above theglass transition temperature of the soft segment. In order to preparedevices that will have sufficient stiffness, it is necessary to havethermal transitions such that the material will have high modulus at usetemperature. For example, if a device is going to be used at bodytemperature, then the transition temperature may be higher than 37° C.(example 45-50° C.) so that upon cooling to 37° C. the modulus is highand thereby providing sufficient stiffness. It is also important todesign the device such that it will compensate for lower physicalproperties compared to shape memory metal alloys. Some of the designfeatures may include higher wall thickness; short connectors; or hingepoints at appropriate locations. These materials can overcome some ofthe limitations with viscoelastic polymer properties such as creep andstress relaxation.

SMP can also be prepared by using TPEs prepared from hydrophilicpolymers so that the phase transition can be also occur by physicalchanges due to moisture absorption. Examples of these TPEs arehydrophilic polymer ester amide (Pebax) and hydrophilic polyurethanesprepared by Elf Atochem and CardioTec International, respectively.Devices prepared from these materials will be soft and will be easier toremove after its use.

The shape memory materials may be formed of or at least enclosed withinbiocompatible materials, preferably materials that are approved for usein the human body. For example, medical grade silicone rubber mayenclose a wireform device. This may be achieved through one or moretubular sheaths about the wire or as a coating prepared on the wire.

As shown in FIG. 8, the intravaginal devices also may be enclosed in aflexible bag that may reduce friction during deployment, shield a wireform from view (to be aesthetically pleasing), help control the deviceduring insertion and removal, help the device to stay in place, containabsorbent fibers of a tampon, contain a suppository substance, and/orcreate more contact area for applying pressure to the bladder neck. Thecover may also provide increased friction against the vaginal epitheliumin comparison to a silicone-coated wire form to reduce the likelihood ofundesired movement during use, e.g., becoming skewed. Any medicallyappropriate materials may be used to form the bag, and depending uponthe desired end-use, it may be opaque, light, and/or breathable. Usefulbag materials include those used in the manufacture of tampons, such asnonwoven fabrics and plastic film, including apertured films. The bagitself may also be apertured.

The device preferably includes a withdrawal element such as a removalstring. This may be crisscrossed between the struts of the device tocreate a “cinch sac” mechanism. Any string or cord known in the sanitaryprotection art may be useful for this purpose. As the strings are pulledduring removal, the struts are gathered together to create a smallerdiameter device during removal. Cinching the device at its base may makeremoval of the device more comfortable and easier as it makes thediameter of the device smaller and the shape conducive to remove easily.

The device may be contained within an applicator similar to those knownfor use in delivering tampons and suppositories. The applicator may be apush-type applicator or a retractable applicator. A collar may be addedto control the depth of insertion.

EXAMPLES

The following examples are illustrative of devices according to thepresent invention. The claims should not be construed to be limited tothe details thereof.

Prototype devices were modeled in shape and scale after existing,predicate vaginal pessary devices. There were two geometries presentedfor this device. The expanded stent device was approximately 35 mm indiameter and 55 mm long. The first of the proposed geometries was asimple S-shaped stent like a ring; the second resembled the form of ahandled basket and was modeled in the form of the classic “ring”pessary. In its design the “basket” portion was approximately 25 mm highand the “handle” made up the balance of the overall length.

Both are assemblies of four known medical materials. The collapsedvaginal stents were enclosed in a commercial plastic tampon applicator.The working assemblies were made up of a nickel-titanium wire form(Nitinol), which was covered by a medical grade silicone rubber(silastic) tube. This covered wire form “stent” was placed in aheat-sealed bag made of the same standard non-woven polypropylenematerial used in tampon covers. This covered device was made to beeasily removable by the addition of a tampon cotton string, as a cinchand removal pull.

The nickel-titanium wire used in these prototypes was the same alloy asused in vascular systems. Post-shape-setting processing of the metaldoes not effect corrosion and biocompatibility of the device. Thesilicone tubing was also a known medical grade material. The silastictubing was Dow Q7-4750.

The general procedure was to shape an SE508 NiTi into the design on aform using one or multiple steps heating the fixture and form to about500° C. for at least one minute for each step. Any excess wire was cutfrom the form. As is known in the art, the wire may be chemically etchedto provide further biocompatibility. The wire was enclosed in a rubberypolymer coating such as silicone assuring to fasten the wire ends suchthat they may not puncture the surface.

Example 1 Rabbit Flat Pessary

Approximately 1 foot of straightened and etched SE508 wire, 0.0315″diameter was obtained. The tool pictured in FIG. 9 was made usingconventional techniques known in stent art. In a smooth upswing, thewire was wrapped around the pins in the following order to create thepattern: P7, P3, P1CC, P3, P6CC, P3, P6, P4, P8CC, P5, P8, P5, P2CC, P5,P7, P1CC, P3, P7 (the wrapping was clockwise, unless indicated by “CC”).The zigzag wrapping pattern was smoothly discontinued and the final endof the wire was poked through holes in the fixture to secure it. A largehose clamp was wrapped around the fixture, over the zigzag portion. Theclamp was tightened to keep the wires in position, but not so much as tocompress the wires to the surface of the fixture. The wound wire washeat treated on the fixture for 3 minutes in a 505 C (calibrated) saltpot, then quenched with water. The heat treated wire was removed fromthe fixture by unwinding it. The wire was trimmed at point 3 allowingfor overlap along the “ear” and the overlapping wires were wrapped tohold them together with NiCr wire as shown in FIG. 9. A secondary heattreatment fixture shown in FIG. 10 was made according to methods knownin the art. The wire was aligned to form onto the fixture. The ends ofthe wire were ground to remove sharp and jagged edges.

The wire form component was passivated by methods known in the art tooptimize biocompatibility. Some wire form components were etched orchemically processed to optimize biocompatibility. The parts were movedto a clean room and dipped in denatured alcohol before being placed on aclean table. All tools were cleaned with isopropyl alcohol as well asgloved hands before touching parts from denatured alcohol solution.Tubing was cleaned with Isopropyl alcohol by dripping through with adisposable pipette. The tube was dried by wicking onto a paper towel.The tube was filled with 2-4 inches of lubricant mineral oil from asyringe. Pressed fingers were run along the tube to spread the oilevenly along the inside. The tubing was slid over the wire carefullypaying attention that the wire ends did not poke through the tubing. Thetubing was pulled back to expose both wire ends. The ends were lined upso that the ear rests naturally. Forceps were used to hold the tubingback from the wire ends. Shrink tube was placed across the wire ends andheated to hold wire ends in place. The tubing was slid over the shrinktube section. Tubing ends were overlapped by at least ½ cm by pressingthe ends together.

Example 2 Flower Flat Pessary

Approximately 1 foot of straightened and etched SE508 wire, 0.0315″diameter was obtained. The tool pictured in FIG. 9 was made usingconventional techniques known in stent art. In a smooth upswing, thewire was wrapped around the pins in the following order to create thepattern: P6, P3, P1CC, P3, P6, P4, P7,6,3,1CC,3,6,4,7,5,2CC,5,7,4,6,3,1CC,3.P5, P2CC, P5, P7, P4, P6, P3,P1CC, P3. The zigzag wrapping pattern was smoothly discontinued and thefinal end of the wire was poked through holes in the fixture to secureit. A large hose clamp was wrapped around the fixture, over the zigzagportion. The clamp was tightened to keep the wires in position, but notso much as to compress the wires to the surface of the fixture. Thewound wire was heat treated on the fixture for 3 minutes in a 505 C(calibrated) salt pot, then quenched with water. The heat treated wirewas removed from the fixture by unwinding it. The wire was trimmed atpoint 3 allowing for overlap along the “ear” and the overlapping wireswere wrapped to hold them together with NiCr wire as shown in FIG. 9. Asecondary heat treatment fixture shown in FIG. 10 was made according tomethods known in the art. The wire was aligned to form onto the fixture.The ends of the wire were ground to remove sharp and jagged edges. Thewire form component was passivated by methods known in the art tooptimize biocompatibility. Some wire form components were etched orchemically processed to optimize biocompatibility. The parts were movedto a clean room and dipped in denatured alcohol before being placed on aclean table. All tools were cleaned with isopropyl alcohol as well asgloved hands before touching parts from denatured alcohol solution.Tubing was cleaned with Isopropyl alcohol by dripping through with adisposable pipette. The tube was dried by wicking onto a paper towel.The tube was filled with 2-4 inches of lubricant mineral oil from asyringe. Pressed fingers were run along the tube to spread the oilevenly along the inside. The tubing was slid over the wire carefullypaying attention that the wire ends did not poke through the tubing. Thetubing was pulled back to expose both wire ends. The ends were lined upso that the ear rests naturally. Forceps were used to hold the tubingback from the wire ends. Shrink tube was placed across the wire ends andheated to hold wire ends in place. The tubing was slid over the shrinktube section. Tubing ends were overlapped by at least ½ cm by pressingthe ends together.

Expansion Pressure Test

Rubber Band Methodology

The expansion pressure test was used to determine the outward pressurethe device was able to exert as it expanded from its compressedinsertion state to its deployed or use state in the body. Equilibrium ofthe expansion pressure and the internal resistance of the bodydetermined the diameter of the device in place.

Sets of rubber bands in a range of sizes were needed. The bands utilizedwere the following sizes; orthodontic, #8, #10 and #12. Some sources ofthese rubber bands are Thomson Orthodontics of Prospect, Ky. and OfficeDepot of Westhampton, N.J. A Chatillon TCD 200 benchtop tensile testerwith a Chatillon DFIS 10 Digital Force Gauge was used to determine theforce vs extension relation of the rubber bands. A small hook to securethe rubber bands was attached to the load bearing extension of the forcegauge and a second hook was secured to the base of the tester directlybelow the first hook. The rubber bands were looped around these hooksfor testing.

Each set type of rubber bands had at least 3 repeats of the followingprocedure done to determine the force vs extension relation. A band washeld between the hooks and the crosshead was adjusted so that there wasno tension on the band but the band had no slack in it. The distancebetween the two hooks was then measured and recorded as the zero forcedistance. This distance was actually one half the resting length of therubber band. The crosshead was moved in increments of 5 to 10 mm at aspeed of 12.5 mm/minute to stretch the rubber band. At each point theforce was recorded. Provided the bands did not break, data was gatheredup to about 70 mm crosshead displacement. Smaller size bands did notallow this much stretch. Average force level at each extension wasaveraged and a force vs extension curve for each band was plotted and isshown in FIG. 11.

Once the band force extension curves were obtained, the pressure vsexpansion characteristics of the devices were determined. The operatorchose a type of band to use. The operator compressed the device by handand placed the rubber band around the device so that when the operatorreleased the device to expand, it opened, the band stretched and thedevice and rubber band came to an equilibrium position. The bandgenerally needed to be centered in the working section. For cylindricalworking sections, the diameter of the band and device were measured andthe perimeter was calculated as 3.14*diameter. This measured diameter isthe equivalent diameter for a cylindrical stent. For rectangulardesigns, the perimeter of the band and the separation of the two faceswere measured. For rectangular designs the separation of the two facesmeant to reside adjacent to the anterior and posterior walls of thevagina are the equivalent diameter.

The perimeter value was divided by two and the force in the band wasinterpolated from the band force vs displacement extension curve(example FIG. 11). For cylindrical working portions, expansion pressurewas determined by dividing the force by the product of the equilibriumdiameter and the axial length. For rectangular devices it was determinedby dividing the force by the product of the product of the length timesthe width of the working portion.

The operator repeated the device testing procedure with a range of Bandsizes so that a pressure vs size data points was obtained across therange of interest, ˜20 to 40 mm. In addition to using multiple sizes,multiple bands of the same size were used together to generate datapoints. In this case the force or pressure was multiplied by the numberof bands used. A resulting diameter vs pressure curve for a device isshown in FIG. 12.

Linear Compressions Test Methodology:

The outward pressure the device exerts at various compression states(insertion to in-use to during stress) was measured using a simplelinear scale (Mettler PK 4800 scale). The pressure the device exerted aswell as the diameter of the device were measured and recorded.

The device is tested by placing the device between the scale and acustom-made arm that compresses the device at known, incrementaldistances, measured in mm. The device was measured first at its freestate (i.e., for rabbit: 20 mm) and then slowly compressed in increments(i.e. 1 mm or 5 mm). The force that the device exerts on the scale atknown compression increments was measured in grams. The pressure wascalculated by converting the force measurement from grams topounds-force. The pounds-force was then converted to PSI units bydividing the pound-force by the contact area of the device. The contactarea of the device was defined as the working portion of the device. ThePSI units were then converted into cm H₂O pressure. The resulting devicediameter (mm) versus pressure (cm H₂O) was then graphed. FIG. 13 showsthe diameter versus pressure curves for the rabbit and flower devices.

1. A method of making an intravaginal stent comprising the steps of: a)forming a working portion comprising a shape memory material and havingopposed faces to provide support to an associated urinary system; and b)forming an anchoring portion capable of maintaining the working portionin place during use.
 2. A method of making an intravaginal stentcomprising the steps of: a) forming a working portion comprising a wireform having opposed faces to provide support to an associated urinarysystem, wherein the wire form comprises a shape memory material; and b)forming an anchoring portion comprising a wire form operativelyconnected to and capable of maintaining the working portion in placeduring use.
 3. A method of making an intravaginal stent comprising thesteps of: a) forming a working portion comprising a wire form havingopposed faces to provide support to an associated urinary system,wherein the wire form comprises a shape memory material; b) forming ananchoring portion comprising a wire form operatively connected to andcapable of maintaining the working portion in place during use; c)enclosing the wire form of each of the working portion and anchoringportion within a biocompatible material; d) attaching a withdrawalmechanism to the stent; e) enclosing the stent within a bag; and f)placing the bagged stent in an applicator for delivery into the vagina.4. The method according to claim 3 wherein the biocompatible materialcomprises silicone.
 5. The method according to claim 4 wherein thebiocompatible material comprises a tubular silicone sheath.
 6. Themethod according to claim 4 wherein the biocompatible material comprisesa silicone coating.
 7. A method of making an intravaginal stentcomprising the steps of: a) forming a working portion comprising a shapememory material formed into a wire form having a plurality of strutsthat at least partially define and support opposed faces of the workingportion, which opposed faces are capable of providing support to anassociated urinary system; b) forming an anchoring portion comprising awire form operatively connected to and capable of maintaining theworking portion in place during use; c) enclosing the wire form of eachof the working portion and anchoring portion within a biocompatiblematerial; d) operatively connecting a proximal end of a withdrawalstring to at least two struts of the working portion such that tensionon a distal end of the withdrawal string urges the opposed faces of theworking portion together; e) enclosing the stent within a bag; and f)placing the bagged stent in an applicator for delivery into the vagina.